Supporting elements or bearing elements of the type in question may take the form, for example, of mattresses. Mattresses of this kind typically consist of foam materials, and the mattresses may especially consist of multiple superposed foam layers. In order to increase the lying comfort of such mattresses, it is customary to undertake what is called zoning in mattresses. Zoning of this kind forms zones with different elastic properties, i.e. different degrees of yielding, distributed over the area of the mattress. This takes account of the fact that a mattress should have a different degree of yielding in the leg region, for example, than in the back region. Formation of zoning of this kind in multilayer mattresses is typically accomplished by incorporating cavities in a localized manner into a middle mattress layer with oscillating blades. On the upper and lower sides of this middle mattress layer, fully continuous upper and lower mattress layers are then applied in each case.
DE 10 2015 100 816 B3 discloses a process for producing a body-supporting element formed by a mattress, a cushion, a seat or part of a seat, comprising the process steps of defining print data which form a person-specific three-dimensional support structure and the production of the body-supporting element using the print data by means of a 3D printer. With the print data, it is possible to produce regions of different elasticity through the formation of cavities of different sizes and/or different number by means of the 3D printer.
It is stated that, in the process according to DE 10 2015 100 816 B3, production of the body-supporting element can be accomplished using elastic materials which, in the printing process conducted with the 3D printer, are mixed with a binder. Elastic materials used may be elastomeric materials, especially plastics. The 3D printer may have spraying means, in which case elastic materials are sprayed from first spraying means and binder from second spraying means. The elastic materials may be in powder form.
DE 10 2015 100 816 B3 does not make any statements as to whether the elastomeric material forms a porous body. It is stated that, by means of the 3D printer, depending on the print data, regions of different elasticity of the body-supporting element are generated through the formation of cavities of different sizes and/or different number. In order to obtain a three-dimensional variation of the elasticity of the mattress 3, it is possible to incorporate cavities in a controlled manner at particular sites in the mattress in the 3D printer. A void volume at a particular site is generated by not spraying any binder via the second spraying means, such that the elastomeric material sprayed via the first spraying means cannot bond there with the binder to form a material structure. Alternatively, it is also possible for no elastomeric material to be sprayed via the first spraying means, such that there is no wastage of pulverulent elastomeric material.
DE 10 2015 100 816 B3 states that the cavities generated with the 3D printer can have any desired geometries, and these may especially take the form of inclusions that may be surrounded on all sides by the material structure of the mattress. In addition, it is stated that the cavities can be generated in different sizes, and it is especially also possible here for very small cavities to be generated, which means that particularly high spatial resolution of the variation in the elastic properties of the mattresses is to be achieved.
Traditionally, flexible polyurethane foams are used in large volumes for the production of mattresses, cushions and the like, which is documented in numerous patent and non-patent publications. By contrast, reports relating to materials that could be characterized as foams produced by additive methods are less common.
The publication by Maiti, A. et al. “3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response”, Sci. Rep. 6, 24871; doi: 10.1038/srep24871 (2016) describes materials formed from polydimethylsiloxane elastomer (PDMS) that are produced by means of the direct ink writing method. The material was built up layer by layer, with each layer composed of equally spaced PDMS cylinders of diameter 250 μm.
WO 2012/028747 A1 relates to a process for producing a three-dimensional object from a construction material by an additive layer construction method, in which, proceeding from material characteristics of the construction material and defined properties of the object to be manufactured, an internal structure of the object comprising a grid structure is calculated and the three-dimensional object with this internal structure is produced by the additive layer construction method, such that it has the defined properties.
An important criterion for the perception of comfort in a body-supporting element, for example, a mattress or cushion, is the extent to which the material of the element permits exchange of air through the element with the surrounding air. Without this exchange of air, it would not be possible either for heat to be removed from the human body, which leads to increased perspiration, or for moist air from perspiration from the human body or from a washing process to be transported away.
The problem addressed by the present invention is that of at least partly overcoming at least one drawback of the prior art. A further problem addressed by the present invention is that of providing a porous body suitable for load-bearing for perspiring bodies which permits optimized exchange of air (in order to provide maximum comfort for the perspiring body). A further problem addressed by the invention was that of providing a porous body which, in terms of its perception of comfort for a user, is comparable to a conventional mattress or cushion. An additional problem addressed by the invention was to be able to produce a porous body in a very cost-efficient and/or individualized and/or resource-conserving manner.